The present invention relates generally to tube loading systems, and more particularly, is directed to a tube loading system that eliminates the need for a pocket wheel.
In order to separately load hollow tubes, for example, empty toothpaste tubes having their bottom ends open, the tubes are provided in stacked or side by side relation on a conveyor. The tubes travel from the conveyor into a chute which conveys and transfers the tubes to a rotatable pocket wheel. The pocket wheel includes a plurality of pockets or recesses along the outer periphery thereof and all tubes that are conveyed through the chute are deposited one at a time into a corresponding pocket during rotation thereof.
A pin chain moves adjacent to the pocket wheel and is provided with a plurality of pins. Each pin is aligned with a pocket. Thus, the tubes are deposited in the pockets and then rotated to a position where one or more air jets blow each tube out of the respective pocket and onto a respective pin. The pins are then moved by the chain to another location downstream thereof. The tubes are then stripped by a stripper wheel from the pins and supplied to another pocket wheel and then onto a mandrel for printing on the tubes.
In order to prevent the tubes from falling out of the pockets before they are transferred to a respective pin, a shield surrounds a portion of the pocket wheel.
However, various problems result with this arrangement. Specifically, a new pocket wheel must be provided each time that the diameter of the tubes substantially changes in order to change the dimensions of the pockets which carry the tubes. Thus, there may be a plurality of pocket wheels for an entire line of tubes. The pocket wheels are relatively large and expensive items.
In addition, because the tubes are not filled and are open at one end, they can be relatively flexible. As a result, they tend to become flattened somewhat. In this regard, a tube may deform and be caught between the end of the chute and another tube already in the receiving pocket, which results in jamming and a consequent shut-down of the machine.
There are many variations of the above arrangement. For example, the pocket wheel can be made of axially sliding individual pockets having a vacuum associated therewith, with the pockets axially sliding to move the tubes onto the pin chain. However, there is a mechanical sliding motion for each pocket, rendering the arrangement very complicated in structure and costly, and also suffering the same disadvantages as discussed above.
Prior copending U.S. patent application Ser. No. 09/151,458 overcomes many of the disadvantages of the above prior art. In this arrangement, the tubes are held by a vacuum through a single belt having a V-shaped configuration. However, the V-shaped belt is a custom made item, and must be molded specifically for this purpose.
It would therefore be preferable to use flat belts or round belts having a circular cross-section, which are common commercial items, to obtain a two line contact with the tubes. Such flat or round belts are also easy to splice so that particular lengths can easily be formed.